1. Field of the Invention
The invention relates to an exhaust heat recovery system that recovers exhaust heat of exhaust gas through heat exchange with a coolant.
2. Description of the Related Art
For example, Japanese Patent Application Publication No. 2005-16477 discloses an exhaust heat recovery device in which a coolant-exhaust heat exchanger is provided between a catalytic converter and a muffler that constitute an exhaust system of a motor vehicle. This coolant-exhaust heat recovers exhaust heat by exchanging heat between exhaust gas and the engine cooling water.
However, the engine cooling water may be overheated due to heat (e.g., conductive heat) which is transferred from the catalytic converter with large heat capacity when the engine cooling water stops circulating, for example.